<DropdownListPreview Data="@Items"
                        @bind-Value="@ValueField"
                        TextField="Text"
                        ValueField="Value">
</DropdownListPreview>
<div>双向绑定对象值：@ValueField</div>

@code {
    private object ValueField { get; set; } = "2";

    private List<SelectedItem> Items { get; set; } = new List<SelectedItem>
    {
        new SelectedItem{ Text="北京",Value="0"},
        new SelectedItem{ Text="上海",Value="1"},
        new SelectedItem{ Text="广州",Value="2"},
    };
}